Field of the Invention
This invention relates generally to electrolytes for use in electrochemical cells that employ alkali metals, and, more specifically, to fluorinated electrolytes for use in lithium-containing batteries.
Batteries based on lithium ion transfer work best with electrolytes that have high ionic conductivities and high stabilities. High ionic conductivities are useful because they facilitate ionic transfer, resulting in high power and low polarization. Highly stable batteries are those that are non-flammable and do not undergo undesired reactions with either anode or cathodes.
Perfluoropolyethers terminated with methoxycarbonyl groups have been reported as lithium ion electrolytes when formulated with lithium bis(trifluoromethane)sulfonimide. These electrolytes were reported to have excellent fire resistance and high lithium ion transference, though the ionic conductivities were not particularly high at about 10−5 S cm−1 at 80° C.
What is needed is an electrolyte that provides high lithium ion transference, excellent stability and high ionic conductivities to realize the full potential of lithium batteries that employ them.